Steam cure of cured in place liner

ABSTRACT

A process for lining an existing pipeline or conduit with a flexible resin impregnated cured in place liner by pulling in the liner and inflating an eversion bladder with air and curing the liner with flow-through steam without loss of pressure is provided. The bladder is stored in a pressure bladder canister coupled to a pressurized downtube and eversion elbow. The bladder is everted by introducing pressurized air into the canister As the bladder reaches the distal manhole, it enters a receiving canister where it is punctured while maintaining air pressure within the bladder a pinch valve between the downtube and elbow isolates the inverted bladder so that steam can be introduced into the bladder to cure the resin and exhaust through the receiving canister. The bladder is then removed and lateral service reinstated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 11/268,388filed on Nov. 7, 2005, now U.S. Pat. No. 7,108,456 issued on Sep. 19,2006, which is a continuation of application Ser. No. 10/760,513, nowU.S. Pat. No. 6,969,216, issued on Nov. 29, 2005, filed on Jan. 20,2004, which is a divisional of application Ser. No. 10/404,183, filed onApr. 1, 2003, now U.S. Pat. No. 6,679,293, which is a continuation ofapplication Ser. No. 10/098,974 filed on Mar. 14, 2002, now U.S. Pat.No. 6,539,979 issued on Apr. 1, 2003, which is a continuation ofapplication Ser. No. 09/927,189, filed Aug. 10, 2001, now abandoned.

BACKGROUND OF THE INVENTION

This invention relates to a method for installation of a cured in placeliner by pulling in and inflating the liner and more particularly to amethod of trenchless rehabilitation of an existing conduit by pulling aresin impregnated liner into the existing conduit everting an inflationbladder stored in a pressurized bladder canister into the liner byintroducing air into the canister, isolating the canister andintroducing continuous flow-through steam into the bladder without lossof pressure in the bladder and to the apparatuses for practicing themethod.

It is generally well known that conduits or pipelines, particularlyunderground pipes, such as sanitary sewer pipes, storm sewer pipes,water lines and gas lines that are employed for conducting fluidsfrequently require repair due to fluid leakage. The leakage may beinward from the environment into the interior or conducting portion ofthe pipelines. Alternatively, the leakage may be outward from theconducting portion of the pipeline into the surrounding environment. Ineither case, it is desirable to avoid this leakage.

The leakage may be due to improper installation of the original pipe, ordeterioration of the pipe itself due to normal aging or to the effectsof conveying corrosive or abrasive material. Cracks at or near pipejoints may be due to environmental conditions such as earthquakes or themovement of large vehicles on the overhead surface or similar natural orman made vibrations, or other such causes. Regardless of the cause, suchleakages are undesirable and may result in waste of the fluid beingconveyed within the pipeline, or result in damage to the surroundingenvironment and possible creation of a dangerous public health hazard.If the leakage continues it can lead to structural failure of theexisting conduit due to loss of soil and side support of the conduit.

Because of ever increasing labor and machinery costs, it is increasinglymore difficult and less economical to repair underground pipes orportions that may be leaking by digging up and replacing the pipes. As aresult, various methods had been devised for the in place repair orrehabilitation of existing pipelines. These new methods avoid theexpense and hazard associated with digging up and replacing the pipes orpipe sections, as well as the significant inconvenience to the public.One of the most successful pipeline repair or trenchless rehabilitationprocesses that is currently in wide use is called the Insituform®Process. This Process is described in U.S. Pat. Nos. 4,009,063,4,064,211 and 4,135,958, the contents of all of which are incorporatedherein by reference.

In the standard practice of the Insituform Process an elongated flexibletubular liner of a felt fabric, foam or similar resin impregnablematerial with an outer impermeable coating that has been impregnatedwith a thermosetting curable resin is installed within the existingpipeline. Generally, the liner is installed utilizing an eversionprocess, as described in the later two identified Insituform patents. Inthe eversion process, radial pressure applied to the interior of aneverted liner presses it against and into engagement with the innersurface of the pipeline. However, the Insituform Process is alsopracticed by pulling a resin impregnated liner into the conduit by arope or cable and using a separate fluid impermeable inflation bladderor tube that is everted within the liner to cause the liner to cureagainst the inner wall of the existing pipeline. Such resin impregnatedliners are generally referred to as “cured-in-place-pipes”or “CIPPliners” and the installation is referred to a CIPP installation.

The CIPP flexible tubular liners have an outer smooth layer ofrelatively flexible, substantially impermeable polymer coating theoutside of the liner in its initial state. When everted, thisimpermeable layer ends up on the inside of the liner after the liner iseverted during installation. As the flexible liner is installed in placewithin the pipeline, the pipeline is pressurized from within, preferablyutilizing an eversion fluid, such as water or air to force the linerradially outwardly to engage and conform to the interior surface of theexisting pipeline. Cure is initiated by introduction of hot water intothe everted liner through a recirculation hose attached to the end ofthe everting liner. The resin impregnated into the impregnable materialis then cured to form a hard, tight fitting rigid pipe lining within theexisting pipeline. The new liner effectively seals any cracks andrepairs any pipe section or pipe joint deterioration in order to preventfurther leakage either into or out of the existing pipeline. The curedresin also serves to strengthen the existing pipeline wall so as toprovide added structural support for the surrounding environment.

When tubular cured in place liners are installed by the pull in andinflate method, the liner is impregnated with resin in the same manneras the eversion process and positioned within the existing pipeline in acollapsed state. A downtube, inflation pipe or conduit having an elbowat the lower end typically is positioned within an existing manhole oraccess point and an everting bladder is passed through the downtube,opened up and cuffed back over the mouth of the horizontal portion ofthe elbow. The collapsed liner within the existing conduit is thenpositioned over and secured to the cuffed back end of the inflationbladder. An everting fluid, such as water, is then fed into the downtubeand the water pressure causes the inflation bladder to push out of thehorizontal portion of the elbow and cause the collapsed liner to expandagainst the interior surface of the existing conduit. The eversion ofthe inflation bladder continues until the bladder reaches and extendsinto the down stream manhole or second access point. At this time theliner pressed against the interior surface of the existing conduit isallow to cure. Cure is initiated by introduction of hot water into theinflation bladder which is circulated to cause the resin in theimpregnated liner to cure.

After the resin in the liner cures, the inflation bladder may be removedor left in place in the cured liner. If the inflation bladder is to beleft in place, the bladder will generally be one that has a relativelythin resin impregnable layer on the inside of the impermeable outerlayer. In this case, the impregnable layer after eversion will cause thebladder to adhere to the resin impregnated layer of the liner as is wellknown in the art. At this time, entry into the manhole or access pointis required to open the liner to release the water used to inflate thebladder and to cut off the ends extending into the manholes. When theinflation bladder is to be removed, it may be removed by pulling at theevasion end on a holdback rope attached to the trailing end of theinflation bladder used to control the speed of the eversion. This isgenerally done after puncturing the bladder at the receiving end torelease the water used to evert the bladder and initiate the resin cure.Finally, the downtube can then be removed and service can be reconnectedthrough the lined pipeline. If intersecting service connections arepresent, they would be reopened prior to resumption of service throughthe lined pipeline.

When a cured in place liner is installed using the pull in and inflatemethod, the outer impermeable layer of the liner remains pressed againstthe interior surface of the existing conduit. Certain advantages may beattained by this method of installation because the resin in the resinimpregnable layer of the liner is trapped between two impermeablelayers, namely the outer coating of the liner and the inflation bladderon the inside. Accordingly, there is little or no resin migration out ofthe resin impregnable layer of the liner. In a pull in and inflateinstallation, the liner coating need not be as strong as required in aninstallation by eversion, because the coating is not subjected to thepressure head required to evert the liner using the eversion process.Additionally, the coating does not come into contact with hot fluidcirculating during the resin cure cycle. Thus, the liner may be of moreuniform thickness in a pull in and inflate using an inflation bladdercured in place process compared to when the liner itself is everted.

While the pull in and inflate method has these advantages, theinstallation process is somewhat more complex than an eversion of theresin impregnated liner. Conventional pull in and inflate methodsrequires banding the inflation bladder to the downtube elbow andsecuring the collapsed liner already positioned in the existing pipelineto the downtube. This requires work within a restricted manhole space.Additionally, at the end of the installation, the inflation bladder mayneed to be removed after being cut at the distal end to release thewater used as the inflation fluid.

While the pull in and inflate method utilizing water does have thevarious advantages noted above, the shortcomings tend to increase laborcosts which are a significant aspect of the installation process.Accordingly, it is desirable to provide a rehabilitation method usingpull in and inflate, wherein the liner is inflated with an eversionfluid, such as air, and the resin is cured by steam a heated curingfluid, such as flows through the inflated bladder, to take advantage ofthe energy available in the heated fluid to provide an installationmethod which is faster and more efficient economically than variousrehabilitation methods currently practiced.

SUMMARY OF THE INVENTION

Generally speaking, in accordance with the invention, a method ofrehabilitation of an existing pipeline by pull in and inflateinstallation of cured in place liners using air to inflate an inflationbladder and curing with flow-through steam without loss of pressure inthe liner is provided. A resin impregnated liner is pulled into theexisting pipeline to be repaired and cut to extend beyond the ends ofthe pipeline. An inflation bladder stored in a pressurized bladdercanister is attached to an inflation elbow that is placed in theupstream or eversion manhole and the collapsed liner is secured to theoutlet end of the bladder on the elbow. Pressurized air is introducedinto the bladder canister to evert the bladder. When the bladderapproaches the downstream access point, eversion is stopped and theliner is attached to a receiving canister in the downstream or receivingmanhole. The bladder is then allowed to evert further into the receivingcanister, forming a seal and is punctured. Air pressure is maintained inthe bladder and exits the receiving canister through an exhaust lineattached to the distal end of the canister.

While maintaining pressure in the bladder canister and bladder, a pinchvalve at the inlet side of the eversion elbow is closed. Steam isintroduced into the elbow downstream of the valve and passes through thebladder to initiate the cure and exits through the canister exhaust.After the resin in the liner is cured, the steam is turned off and theair pressure is adjusted to maintain pressure in the bladder andmaximize cooling. The valve is opened and the inflation bladder is thenwithdrawn by de-everting. Any condensate in the bladder is removedthrough a condensate trap in the elbow in the eversion manhole.

In a preferred embodiment of the invention, an easement vehicle carriesa pressure bladder canister with a spooled inflation bladder ofappropriate length on a staging spool mounted there in. The vehicle ispositioned at the eversion access and includes valves and regulators forapplying pressurized air to the canister for eversion of the bladder andsteam for curing of the liner and removal of the bladder after cure. Ina most preferred aspect of the invention, the inflation fluid is airwhich is introduced into the bladder canister for inflating the bladder.This allows the precise control of the speed of the everting bladder.After the bladder inflates the liner, it enters a receiving canisterhaving a puncturing element positioned in the receiving manhole. Thebladder is sealed against the canister wall and is punctured to allowair to exit through an exhaust port. The elbow valve is sealed about thebladder and steam is introduced at the eversion elbow. The steam flowsthrough the bladder to cure the resin quickly and completely withoutloss of pressure in the bladder. This maintains hot curing fluids safelybelow ground, a safe distance away from any personnel.

Accordingly, it is the object of the invention to provide an improvedmethod for rehabilitation of an existing pipeline by the installation ofa cured in place liner by the pull in and inflate method utilizing aninflation bladder stored in a pressurized bladder canister.

Another object of the invention is to provide an improved method forpull in and inflate installation of a cured in place liner byintroducing a pressurized eversion fluid into the a bladder canister tocontrol eversion of the bladder.

A further object of the invention is to provide an improved method ofinstallation of a cured in place liner by pull in and inflate whereinthe bladder canister is isolated by a pinch valve and a pressurizedcuring fluid is introduced into the bladder to cure the resin.

Yet another object of the invention is to provide an improved method forpull in and inflate installation of a cured in place liner byintroducing pressurized air as a eversion fluid into the a bladdercanister to control eversion of the bladder.

It is a further object of the invention is to provide an improved methodof installation of a cured in place liner by pull in and inflate whereinthe bladder canister is isolated from the bladder canister by a pinchvalve and steam as a curing fluid is introduced into the bladder to curethe resin.

Still another object of the invention is to provide an improved methodfor pull in and inflate installation of cured in place liner byautomatically puncturing the bladder as it enters a receiving canisterin the downstream manhole.

Still another object of the invention is to provide a bladder canister,pressurized downtube, pinch valve and elbow assembly to provide forsteam flowing through the everted inflation bladder.

Still another object of the invention is to provide an improved easementunit for use in the installation of cured in place liner by the pull inand inflate method including a pressurize bladder canister including astaging reel for holding the length of inflation bladder to be used.

Still another object of the invention is to provide a manifold toregulate air to be fed to a pressure bladder canister and eversion elbowto effect eversion of an inflation bladder and air and steam to theflow-through steam for curing.

Still other objects and advantages of the invention will in part beobvious and will in part be apparent from the specification.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to the others, and theapparatuses possessing the features, properties and relation of elementswhich are exemplified in the detailed disclosure and the scope of theinvention will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the invention, reference is had to thefollowing description taken in connection with the accompanying drawingsin which:

FIG. 1 is a perspective view of a length of a typical resin impregnablecured in place liner suitable for use in lining an existing pipeline inaccordance with the invention;

FIG. 2 is a perspective view of the liner of FIG. 1 with the leading endfolded with a cable secured to it for pulling the liner into theexisting pipeline;

FIG. 3 is a cross-sectional elevational schematic view showing pullingin of a resin impregnated cured in place liner of the type illustratedin FIGS. 1 and 2 from a downstream or receiving manhole to an upstreamor eversion manhole with an easement vehicle having a pressure bladdercanister at the start of the installation process to line an undergroundconduit;

FIG. 4 is a cross-sectional elevational schematic view of the collapsedcured in place liner of FIG. 3 after it is positioned within theexisting conduit at the start of the installation in accordance with theinvention;

FIG. 5 is an elevational view of the eversion apparatus, including apressurized bladder canister, a pressurized downtube, pinch valve andeversion elbow constructed and arranged in accordance with the inventionwith the eversion bladder and starter sleeve installed;

FIG. 6 is a cross-sectional elevational view showing the eversionapparatus of FIG. 5 inserted into the liner at the start of the eversionin accordance with the invention;

FIG. 7 is a detailed sketch of the air and steam piping connected to theeversion elbow in the eversion manhole during an installation;

FIG. 8 is a detailed schematic view of the manifold for controlling airand steam temperature and volume in the process; and

FIG. 9 and FIG. 10 are cross-sectional elevation view of receivingcanisters positioned in the receiving manhole before completion ofeversion of the bladder.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a flexible cured in place liner 11 of the typegenerally well known in the art. Liner 11 is formed from at least onelayer of a flexible resin impregnable material, such as a felt layer 12having an outer impermeable polymer film layer 13. Felt layer 12 andfilm layer 13 are stitched along a seam line 14 to form a tubular liner.A compatible thermoplastic film in a form of a tape or extruded material16 is placed on or extruded over seam line 14 in order to ensure theimpermeability of liner 11. In the embodiment illustrated in FIG. 1 andused throughout this description, liner 11 includes an inner second feltlayer 17 also stitched along a seam line 18 which is positioned at apoint in the tube other than the location of seam line 14 in outer feltlayer 12. Liner 11 has a leading end 19 with a continuous length storedin a refrigeration unit 21 (FIG. 3) to suppress early cure of the resin.Liner 11 is cut to a desired length after being pulled into the existingpipeline.

Liner 11 of the type illustrated in FIGS. 1 and 2 is impermeable towater and air. This will allow use in an air or water eversion asdescribed above. However, in a pull in and inflate installation inaccordance with the invention, the liner need only be sufficientlyimpermeable to allow for suitable wet out and retention of resin and toprevent damage to the liner as it is pulled into the existing pipeline.

For larger liner diameters, several layers of felt material may be used.Felt layers 12 and 17 may be natural or synthetic flexible resinabsorbable material, such as polyester or acrylic fibers. Impermeablefilm 13 in outer layer 12 may be a polyolefin, such as polyethylene orpolypropylene, a vinyl polymer, such as polyvinyl chloride, or apolyurethane as is well known in the art. In the initial step in alltrenchless rehabilitation installations, the existing pipeline isprepared by cleaning and videotaping.

Prior to commencing installation pursuant to the method in accordancewith the invention, a curable thermosetting resin is impregnated intothe felt of a liner 33 similar to liner 11 by a process referred to as“wet-out”. The wet-out process generally involves injecting resin intofelt layer or layers 12 and 17 of liner 11 through the end or an openingformed in impermeable film layer 13, drawing a vacuum and passing theimpregnated liner through nip rollers as is well known in the liningart. One such procedure of this vacuum impregnation is described inInsituform U.S. Pat. No. 4,366,012, the contents of which areincorporated herein by reference. A wide variety of resins may be used,such as polyester, vinyl esters, epoxy resins and the like, which may bemodified as desired. It is preferable to utilize a resin which isrelatively stable at room temperature, but which cures readily whenheated.

FIG. 2 shows a leading end 32 of a liner 33 with a winch rope or cable22 secured by a slip knot and three half hitches 23 for pulling liner 33into the pipeline. Leading end 32 of liner 33 and cable 22 may be ducttaped to prevent slip of cable 22 and to seal leading end 32.

Referring now to FIG. 3, an existing pipeline 24 located below a surface25 with a section 26 in need of repair between an upstream opening 27and a downstream opening 28. Pipeline section 26 has a plurality ofcracks 29 and a section of missing pipe material 31. There is firstupstream or access at an upstream manhole U and a second downstreamaccess opening at manhole D. Of course, the installation and steps to bedescribed can be done at either end of pipeline section 26 to berepaired. For convenience, the process in accordance with the inventionwill be described with the eversion proceeding from upstream manhole Uto downstream manhole D.

A conventional jetter is used to pull in winch cable 22 into pipelinesection 26 from upstream manhole U to downstream manhole D. Cable 22 isthen connected to leading end 32 of liner 33. Liner 33 is of the typeshown in FIG. 1, but may have a less robust impermeable film than usedin eversion installations. Liner 33 is pulled from refrigeration unit 21positioned at downstream manhole D into pipeline section 26 to berepaired by a winch 34 positioned on an easement unit 36 on surface 25at upstream manhole U.

Winch 34 may be a stand alone unit positioned on surface 25, or may bemounted on a vehicle, such as easement unit 36. Easement unit 36includes additional apparatuses useful in the installation, such as apressure bladder canister 37 including a length of an inflation bladder38 wound on a staging reel mounted therein. Inflation bladder 38 is animpermeable flexible film in tubular form and flattened for convenientspooling and storage on a staging reel 40.

Bladder 38 may be of a thermoplastic material, such as polyethylene orpolypropylene. If bladder 38 is to be left in place after curing ofliner 33, the interior surface of bladder 38 will have a thin layer ofimpregnable material thereon. This will cause bladder 38 to adherepermanently to liner 38 after cure. Bladder 38 on reel 40 is of a lengtha safe margin longer than the length of pipeline section 26 to berepaired. Typically, an excess of about 2 to 15 percent of bladderlength is placed on staging reel 40 is provided, and preferably about 5to 10 percent in excess.

Referring now to FIG. 4, installation of resin impregnated liner 33using an improved pull in and inflate method in accordance with theinvention is illustrated. Resin impregnated liner 33 is pulled into thepipeline section 26 to be relined with about a foot of liner 39extending into upstream manhole U. A length of excess of liner 41 ofabout eight to ten feet remains in downstream manhole D. Excess 41 maybe held on surface 25 by a piece of tape or rope 42 secured to a sandbag43. Excess liner 41 is provided to accommodate movement of liner 33 asit is expanded.

In the conventional pull in and inflate installation process utilizing awater eversion process, pressure within the bladder and liner ismaintained due to the height of the water column within the downtube.Cure is initiated by exposing the impregnated liner to heat. This isusually accomplished by introducing heated water into the eversion pipeor by circulating hot water through a recirculation hose pulled into theeverting bladder by a hold back rope connected to the trailing end ofthe everting bladder. Generally, cure takes between about 3 to 5 hoursdepending on the type of resin selected and the thickness of the liner.After cure, entry into the downstream manhole is necessary to releasethe heated water after cure prior to removal of the inflation bladder.

FIGS. 5 and 6 illustrate an eversion apparatus including pressurizedbladder canister 37, a pressurized downtube 45 and an eversion elbow 46and a pinch valve 51 at the inlet to elbow 46 to be used in accordancewith a preferred embodiment of the invention. In these Figures, bladdercanister 37 is shown in section mounted on easement unit 36 inaccordance with a preferred embodiment of the invention. Pressurizeddowntube 45 is a 4″ steam hose fitted with standard Chicago fittings 94for coupling to canister 37 and valve 51. Downtube 45 is thus bendableso that simply moving easement unit 36 allows for easy adjustmentdepending on the depth of manhole U. Elbow 46 includes an inlet orvertical section 48 and an outlet or horizontal section 49. A pinchvalve 51 has an air inlet 52 for pressurizing a flexible element thereinto isolate bladder canister 37 and downtube 45 from the interior ofbladder 38 when steam is introduced. Valve 51 may be a spincter valveformed from a flexible element secured within an outer cylindrical wallso that a chamber is formed behind the flexible wall to pressurize theflexible element against bladder 38. Such a value is constructed andoperates similarly to the eversion apparatus described in U.S. Pat. No.5,154,936, the contents of which are incorporated herein by reference.

Bladder canister 37 is formed from a pair of cooperating circular diskframe members 91 forming an enclosure having a bladder outlet 92 and anair inlet 93. A bladder staging spool 40 is mounted for rotation incanister 37. When closed, canister 37 is air tight can withstand morethan at least 5 pounds per square inch and preferably considerably morepressure. The eversion pressure generally applied to air inlet 93 isbetween 3 and 10 psi, preferably about 5 psi. Outlet 92 is fitted with aChicago or similar coupling 94 for easy and secure coupling to downtube45 having a cooperating fitting.

Bladder canister 37 also includes bladder spool 40 mounted for rotationtherein coupled to a chain 97 driven by a motor 98 as shown in FIG. 3.Chain drive 97 facilitates winding the appropriate amount of bladder 38on spool 40 prior to the start of the installation. This can also beutilized to rewind bladder 38 after cure by de-everting it from withincured liner 33.

Inflation bladder 38 wound on staging reel 40 on easement unit 36 is fedthrough downtube 45, valve 51 and elbow 46. Bladder 38 is then cuffedback and banded to horizontal section 49 of elbow 46. The upper portionof downtube 45 is then coupled to bladder outlet of canister 37. Airpressure is applied to air inlet 61 and to bladder 38 sufficient toeffect the eversion. Lubricant is applied to the surface of bladder 38to facilitate movement through downtube 45 and elbow 46 during theeversion of bladder 38.

Horizontal section 49 of elbow 46 is fitted with a flexible startersleeve 58. Starter sleeve 58 is a length of about two feet of flexiblerobust tubular material banded over bladder 38 with at least one bandingstrap 59. Starter sleeve 58 is sufficiently flexible so that when notsupported it will generally lay flat. When attached to horizontalportion 49 of elbow 46, distal end of starter sleeve 58 lies flat asillustrated in FIG. 6. Eversion apparatus 44 is lowered into upstreammanhole U and the flattened end of starter sleeve 58 is inserted intothe upstream end of liner 33 so that the liner overlaps starter sleeve58 by at least about 3 to 6 inches. Care is taken to maintain startersleeve 58 flat to avoid introduction of air into liner 33.Alternatively, liner 33 can be simply secured about bladder 38 bybanding or the like.

Inflation bladder 38 is formed of a tube of thermoplastic film, such asa polyolefin or polyvinyl chloride. A wide variety of thermoplasticmaterials would be suitable, such as polypropylene or polyurethane solong as the material will withstand the temperatures reached duringcure.

Horizontal section 49 of elbow 46 is formed with an air/stream inletport 61 for receiving air for eversion of bladder 38 and steam for cure.In the illustrated embodiment, elbow 46 also includes a condensate drain62 for removing any condensate that forms in bladder 38 during cure andcool down. After inflation bladder 38 and starter sleeve 58 areinstalled, eversion assembly 44 is positioned in upstream manhole U asshown in FIG. 6.

At this time, inflation of liner 33 is ready to begin. At the start, airat about 5 psi is introduced into bladder canister 37 through air inlet93. Once air pressure has stabilized, inflation bladder 38 is permittedto proceed through downtube 45 while maintaining an eversion pressure ofabout 5 psi. In the preferred embodiment, air is introduced from an airinlet source line 63, fed to canister inlet line 93 an air inlet 93through a valve 99 and an air pressure regulator 101 as shown in FIG. 7.Air is then directed to air inlet line 65 for coupling to valve inlet52. As inflation bladder 38 passes through starter sleeve 58 and entersliner 33, starter sleeve 58 will be locked in against the inlet ofpipeline section 26 thereby locking eversion apparatus 44 and elbow 46in place in upstream manhole U. Inflation bladder 38 continues to evertthrough liner 33 until it is brought to a few feet from downstreammanhole D.

Referring to FIG. 9, eversion of inflation bladder 38 is stopped atabout 5 to 10 feet from downstream manhole D. The 5 psi air pressureapplied to bladder canister 37 is maintained when the eversion isstopped. The remaining excess of liner 33 in downstream manhole D is cutto about one foot from the back face of downstream manhole D. A samplemold 67 and two screw-type bands 66 are placed over the end of liner 33.The distal end of liner 33 is then banded about a cylindrical receivingcanister 68 positioned at the back of downstream manhole D. Liner 33 isthen secured to canister 68 with bands 66.

Canister 68 is a cyclindrical section of rigid material having a closedbackwall 69. A bladder punch 71 is mounted to backwall 69. Bladder punch71 is a sharp tapered tubular member coupled to a condensate drain 72through backwall 69. An exhaust coupling 73 is fitted to condensate adrain 72 and an exhaust hose 74 is coupled thereto. The free end ofexhaust hose 74 is positioned outside of downstream manhole D andsecurely positioned so that any steam-air discharge will not cause asafety hazard. At this time, thermocouples and pressure gauges at thesteam-air discharge to read temperature and stream-air flow may beinstalled.

Receiving canister 68 is positioned securely within downstream manhole Dusing sandbags and braces, or other convenient implements. At this time,eversion of bladder 38 is resumed at the 5 psi air pressure. Inflationbladder 38 is everted until the nose of bladder 38 reaches backwall 69of receiving canister 68. When bladder punch 71 punctures the evertingface of bladder 38 air is allowed to exhaust through exhaust hose 74.Pressure in inflation bladder 38 can be controlled by an exhaust value76 on exhaust hose 74.

The details of a valve manifold 64 and the piping attached to steam line65 is shown in FIG. 8. Air enters from air hose 63 through an airpressure regulator 81 and is controlled by an air valve 82. Steamentering from steam hose 77 is regulated by a steam pressure regulator83 and controlled by a steam valve 84. Air and steam are mixed inair/steam hose 65 after passing through air/steam temperature gauge 79and air/steam pressure gauge 78. Air/steam inlet hose 65 is coupled tomanifold 64 and air/steam inlet in elbow 46 by a pair of cam lock, orChicago fittings 86 or any other convenient hose coupling.

At this time air pressure sufficient to create a bulkhead betweenbladder canister and steam inlet 37, for example between about 25 to 60psi, is applied to pinch valve 51. Steam is then introduced intoair/stream inlet port 61 to initiate cure of the resin in liner 33.Steam is provided from a steam inlet hose 77 which is regulated by valvemanifold 64 to provide steam to eversion elbow 46 for curing and anair/steam mixture to air/steam inlet line 65 for controllingtemperature. The air/steam flow is adjusted to maintain a curingpressure of about 4 to 10 psi until the combined air/steam flowtemperatures reach a desired temperature of about 220° F. measured atexhaust hose 74. Depending upon the particular resin and tube thickness,once the cure is complete, steam flow is turned off while simultaneouslyadjusting the air flow to maintain cure pressured. Exhaust valve 76 isadjusted while cooling to about 150° F.

Once the temperature has cooled to the desired level, air flow pressureis reduced to zero, exhaust valve 76 is fully opened and inflationbladder 38 is slowly de-everted. As bladder 38 de-everts, it will sealoff the punctured end. Accordingly, it is desirable to monitor the airflow pressure to prevent pressure build up in bladder canister 37. Anycondensate that may have accumulated in bladder 38 is removed bycondensate drain 62 in elbow 46.

As shown in FIG. 10, a flexible receiving sleeve 87 is secured tocanister 68 by a pair of bands 66. Receiving sleeve 87 is of the samerobust flexible material as starter sleeve 58 and operates in the samemanner to seal expanding liner 33 positioned therein between evertingbladder 38 and the insider of receiving sleeve 87. As bladder 38approaches backwall 69 and is punctured, pressure is maintained withinbladder 38 in the same manner as described in connection with FIG. 9.

After bladder 38 has been totally de-everted, it is safe to enterdownstream manhole D and remove sample mold 67 and receiving canister68. Downtube 45 and elbow 48 are removed from upstream manhole U and anycured liner extending into either manhole is trimmed. At this time,liner 33 is now ready for any lateral reinstatement.

It can readily be seen that the process in accordance with the inventionreadily allows one to attain the advantage of accurately controlling thespeed of an everting inflation bladder by use of a pressure bladdercanister and isolating the everted bladder to curing a resin liner withflow through steam. By practicing the process, a tubular member can beeasily everted through an existing pipeline. By closing a valve at theelbow inlet, pressure can be maintained within the everted tubularmember and steam can be introduced at the elbow access and flow throughthe curing liner to utilize the higher energy available in the steam tocure the resin significantly faster than one can cure utilizingcirculating hot water.

It will thus be seen that the objects set fort above, among those madeapparent from the preceding description, are efficiently attained and,since certain changes may be made and carrying out the above method andin the construction set forth without departing from the spirit andscope of the invention, it is intended that all matter contained in theabove description and shown in the accompanying drawings shall beinterpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended tocover all of the generic and specific features of the invention hereindescribed and all statements of the scope of the invention which, as amatter of language, might be said to fall there between.

1. A method for trenchless rehabilitation of an existing pipeline with aflexible resin impregnated liner, comprising: introducing a flexibleresin impregnated liner into an existing pipeline from a first accesspoint to a second access point; installing an inlet canister into theliner at the first access point; installing an exhaust canister at theopposite end of the liner at the second access point, the exhaustcanister including an exhaust coupling; introducing air into the linerfrom the inlet canister to inflate the liner against the interior wallof the existing pipeline; injecting steam into the inlet canister andadjusting the air/steam mixture through the liner and exit through theexhaust canister; allowing the resin to cure; cease introducing steam;introducing air to cool the cured liner; and allowing the cured liner tocool.
 2. The method of claim 1, comprising; injecting an air/steammixture into the inlet canister to heat the liner to about 220° F. 3.The method of claim 1, comprising: installing the liner by pulling inthe liner from one access point to the other access point.
 4. The methodof claim 1, comprising: installing the liner by inverting the liner intothe existing pipeline from one access point to the other access point.5. The method of claim 4, wherein the liner is inverted through theinlet canister.
 6. The method of claim 3, comprising; inflating theliner by inverting an inflation bladder into the pulled in liner.
 7. Themethod of claim 1, including introducing air into the liner through aninlet port for introduction of fluid in the inlet canister to maintainpressure and; introducing steam into the inlet canister to pass throughthe liner and the exhaust canister.
 8. The method of claim 1, includingintroducing an air/steam mixture into the liner through an inlet portfor introduction of fluid in the inlet canister.
 9. The method of claim4, comprising: installing the liner into the existing pipeline byintroducing the liner through a selectively actuatable valve capable ofallowing a liner to pass therethrough and capable of forming a seal toisolate the interior of an evening liner.
 10. The method of claim 1,including draining condensate through the exhaust canister.
 11. Themethod of claim 3, including inverting a bladder through the inletcanister into the pulled in liner.
 12. The method of claim 11,including; stopping the inverting bladder before reaching the secondaccess point; installing the exhaust canister into the liner of thesecond access point; and continuing the inversion so that the bladderenters the exhaust canister.
 13. The method of claim 1, includingattaching an exhaust hose to the exhaust canister coupling.
 14. Themethod of claim 13, including adjusting the flow of air and/or steamexiting through the exhaust hose.